Generally, police and military training and mock war games are conducted using compressed gas guns which fire projectiles known as paint balls. The object of this type of warfare is to "hit" a target, usually an opponent, with a paint ball to thereby "kill" the opposing player.
Traditionally, the shell of the paint ball is formed with a pair of hemispheres of gelatinous material similar to that used to encase oral medicines such as cold capsules. As is the case with oral medicines, these gelatin shell paint balls are soluble in water. Upon striking the target, a paint ball that functions as intended fractures to mark the victim with coloring agent contained within the paint ball shell.
While these gelatin shell projectiles are traditionally termed paint balls, the coloring agent within the paint ball shell need not necessarily be a paint. To ensure removal of the colored marks left by the paint balls from the skin and clothes of a victim, the coloring agent should exhibit good skin and fabric fugitivity. To this end, water soluble vegetable dyes are often used as coloring agents. Pigments are often added to increase the opacity of the mark left by the breaking paint ball.
One common difficulty with known gelatin shell paint balls is that vegetable dye colorants are usually dissolved in water, a substance which would dissolve the gelatin based shell of the traditional paint ball. In addition, other components which one would like to place in a paint ball, such as smoke or tear gas are greatly limited by the properties of the gelatin shell.
To combat the difficulties presented by the low water tolerance of gelatin, the common water soluble colorant solution is commonly mixed in a mixture of ethylene glycol and polyethylene glycol, or in propylene glycol, in the form of a viscous gel. The use of ethylene glycol is especially troublesome as it is generally considered a toxic substance and contact with human skin is discouraged. While glycol based colorants prevent destruction of the paint ball shell, known gelatin shell paint balls remain exceedingly vulnerable to the vagaries of the external environment. Rain, sweat from a user's body, and even high humidity often alter or even damage the gelatin shell of the paint ball rendering it inaccurate or in many cases unusable.
Further, while the use of glycol gels inhibit the dissolution of the paint ball shell from within, paint balls using glycols suffer from other problems. Perhaps greatest among these problems is the pliability of the gelatinous shell in combination with the viscous glycol. When a victim is struck by a known paint ball, the gelatinous shell yields and stretches undesirably prior to fracturing. Particularly, the forward portion of the paint ball tends to yield somewhat as it contacts the target. As the ball continues to impinge upon the target and fracture, much of the viscous glycol and colorant mixture is displaced to the still intact rear portion of the gelatin shell. As the rearward, still intact, portion of the gelatin shell, containing the viscous colorant mixture, proceeds to impact the target, a cutting leading edge of the rear portion hemisphere engages the target. When the target is a human, this cutting edge often leaves a marked cut, bruise or welt on the victim's skin.
Known paint balls also suffer from inaccuracy, especially when launched from a distance from the target. These paint balls tend to be slightly out of round due to inherent manufacturing difficulties. Even when precise manufacturing techniques are employed, known gelatin shell paint balls are minimally 0.015" out of round. Even this seemingly small oblong shape impart inaccuracy to the fired paint ball.
Additionally, such out of round character impedes the handling of the paint ball through automatic loaders on rapid fire compressed gas paint ball guns. An added difficulty with gelatin paint balls is that the balls often have a very fine seam where the two halves of the gelatin shell have been joined. Because of the delicate nature and inability to withstand exposure to water, this seam cannot readily be removed and further contributes to the inaccuracy of the gelatin shell paint ball when fired.
Further, gelatin shell paint balls have not provided a sufficient density coupled with the launching power of available compressed gas guns to achieve the firing distance sought by many war game players.
Finally, the manufacturing process for producing gelatin shell paint balls is very time consuming. The entire process, from forming of the shell until the ready to ship finished product is complete often takes four days. This long preparation is also often coupled with a high percentage of rejected paint balls.